Re: Performance Problems

[Christoph Neumann <enigma@apu.edu>]

Wow!  What a huge difference!  Thanks for the help.

Could the BDB performance tuning information get a mention in the OpenLDAP
Administrator's Guide?  At the very least, in the "BDB" backend section,
could there be a metion of BDB tuning options with a link to the reference
on Sleepycat's site?  It would have been very nice to have been aware of
that BDB-specific options that are available for tuning.

- Christoph


On Mon, 11 Nov 2002, Ian Logan wrote:

> Its actually a BDB thing and not an OpenLDAP thing.
> In your database enviroment (where the database files are kept)
> create a file called DB_CONFIG. 
> Here's a copy of one I used when loading a database.
> 
> #set the logfile size to 100MB.
> set_lg_max 104857600
> #set the in-memory log buffer size
> set_lg_bsize 262144
> #temporary while we're slapadding the database
> set_flags DB_TXN_NOSYNC
> #set the (per db?) cachesize to 0GB + X bytes, split into N pieces of memory
> set_cachesize 0 209715200 2
> 
> This is all documented in the BerkeleyDB documentation. I dont know if
> the values above will be good for what you're doing, but they worked okay
> for my project.
> Ian
> 
> On Mon, Nov 11, 2002 at 03:43:41PM -0800, Christoph Neumann wrote:
> > OK.  How do I set "DB_TXN_NOSYNC".  I can't find a reference to it in the 
> > Administrators Guide and the Faq-o-matic doesn't specify how to use this 
> > value.  I did find "dbnosync" in "slapd-bdb" man page.  Is that the same 
> > thing?
> > 
> > - Christoph
> > 
> > 
> > On Mon, 11 Nov 2002, Ian Logan wrote:
> > 
> > > Have you tried changing/setting some of the bdb tunables?
> > > You might try setting DB_TXN_NOSYNC while you're running slapadd,
> > > that can make a big difference. You might also want to increase
> > > the size of your bdb cache, if I remember right they default pretty small.
> > > Ian
> > > 
> > > On Mon, Nov 11, 2002 at 01:01:42PM -0800, Christoph Neumann wrote:
> > > > We are testing openldap 2.1.8 as a slave in our production enviroment.  We 
> > > > have experienced serveral problems.  I am wondering if other people are 
> > > > experiencing the same problems or if they have solved some of these 
> > > > problems.
> > > > 
> > > > Some notes about configuration:
> > > > * have about 20,000 entries--mostly "people" entries
> > > > * using BDB backend (db4-4.0.14-14 installed)
> > > > * indexing several fields:
> > > >   index   objectClass             pres,eq
> > > >   index   uid                     pres,eq,sub
> > > >   index   uidNumber               pres,eq
> > > >   index   gidNumber               pres,eq
> > > >   index   mailacceptinggeneralid  eq
> > > >   index   apuidnumber             eq
> > > >   index   rid                     eq
> > > > 
> > > > 1. slapadd is *very* slow compared to the using slapadd with back-ldbm on
> > > >    openldap 2.0.25.  slapadd now takes about 45 minutes, whereas it used to
> > > >    take about 4 minutes.  The only way I have found to fix this, is to
> > > >    slapadd with all the indexes turned off.  Which leads to my next
> > > >    point...
> > > > 2. slapindex is *very* slow.  It takes about 45 minutes to reindex.  It
> > > >    doesn't matter if slapd is running or not.  It still take forever.
> > > > 3. My "uidNumber" index is corrupt.  I rebuilt the database from an LDIF
> > > >    when I upgraded the slave to 2.1.8, so there still must be index
> > > >    corruption issues.
> > > > 
> > > > Anyone else experiencing this?  Anyone have ideas on what might be going
> > > > on?  I have never had OpenLDAP behave this slowly on me before.
> > > > 
> > > > - Christoph
> > > > 
> > > > 
> > > > 
> > > 
> > > -- 
> > > Ian Logan
> > > Information and Communication Technologies
> > > New Mexico State University
> > > Email: ian@nmsu.edu Phone: 505-646-6034 Fax: 505-646-4560
> > > 
> > > 
> > > 
> > 
> 
> -- 
> Ian Logan
> Information and Communication Technologies
> New Mexico State University
> Email: ian@nmsu.edu Phone: 505-646-6034 Fax: 505-646-4560
> 
> 
>